Component: aurora-mysql

This component is responsible for provisioning Aurora MySQL RDS clusters. It seeds relevant database information (hostnames, username, password, etc.) into AWS SSM Parameter Store.

Usage

Stack Level: Regional

Here's an example for how to use this component.

stacks/catalog/aurora-mysql/defaults.yaml file (base component for all Aurora MySQL clusters with default settings):

components:
  terraform:
    aurora-mysql/defaults:
      metadata:
        type: abstract
      vars:
        enabled: false
        name: rds
        mysql_deletion_protection: false
        mysql_storage_encrypted: true
        aurora_mysql_engine: "aurora-mysql"
        allowed_cidr_blocks:
          # all automation
          - 10.128.0.0/22
          # all corp
          - 10.128.16.0/22
        eks_component_names:
          - eks/eks
        # https://docs.aws.amazon.com/AmazonRDS/latest/AuroraMySQLReleaseNotes/AuroraMySQL.Updates.3020.html
        # aws rds describe-db-engine-versions --engine aurora-mysql --query 'DBEngineVersions[].EngineVersion'
        aurora_mysql_engine_version: "8.0.mysql_aurora.3.02.0"
        # engine and cluster family are notoriously hard to find.
        # If you know the engine version (example here is "8.0.mysql_aurora.3.02.0"), use Engine and DBParameterGroupFamily from:
        #    aws rds describe-db-engine-versions --engine aurora-mysql --query "DBEngineVersions[]" | \
        #    jq '.[] | select(.EngineVersion == "8.0.mysql_aurora.3.02.0") |
        #       { Engine: .Engine, EngineVersion: .EngineVersion, DBParameterGroupFamily: .DBParameterGroupFamily }'
        #
        #    Returns:
        #    {
        #       "Engine": "aurora-mysql",
        #       "EngineVersion": "8.0.mysql_aurora.3.02.0",
        #       "DBParameterGroupFamily": "aurora-mysql8.0"
        #     }
        aurora_mysql_cluster_family: "aurora-mysql8.0"
        mysql_name: shared
        # 1 writer, 1 reader
        mysql_cluster_size: 2
        mysql_admin_user: "" # generate random username
        mysql_admin_password: "" # generate random password
        mysql_db_name: "" # generate random db name
        # https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/Concepts.DBInstanceClass.html
        mysql_instance_type: "db.t3.medium"
        mysql_skip_final_snapshot: false

Example configuration for a dev cluster. Import this file into the primary region. stacks/catalog/aurora-mysql/dev.yaml file (override the default settings for the cluster in the dev account):

import:
  - catalog/aurora-mysql/defaults

components:
  terraform:
    aurora-mysql/dev:
      metadata:
        component: aurora-mysql
        inherits:
          - aurora-mysql/defaults
      vars:
        instance_type: db.r5.large
        mysql_cluster_size: 1
        mysql_name: main
        mysql_db_name: main

Example deployment with primary cluster deployed to us-east-1 in a platform-dev account: atmos terraform apply aurora-mysql/dev -s platform-use1-dev

Disaster Recovery with Cross-Region Replication

This component is designed to support cross-region replication with continuous replication. If enabled and deployed, a secondary cluster will be deployed in a different region than the primary cluster. This approach is highly aggresive and costly, but in a disaster scenario where the primary cluster fails, the secondary cluster can be promoted to take its place. Follow these steps to handle a Disaster Recovery.

Usage

To deploy a secondary cluster for cross-region replication, add the following catalog entries to an alternative region:

Default settings for a secondary, replica cluster. For this example, this file is saved as stacks/catalog/aurora-mysql/replica/defaults.yaml

import:
  - catalog/aurora-mysql/defaults

components:
  terraform:
    aurora-mysql/replica/defaults:
      metadata:
        component: aurora-mysql
        inherits:
          - aurora-mysql/defaults
      vars:
        eks_component_names: []
        allowed_cidr_blocks:
          # all automation in primary region (where Spacelift is deployed)
          - 10.128.0.0/22
          # all corp in the same region as this cluster
          - 10.132.16.0/22
        mysql_instance_type: "db.t3.medium"
        mysql_name: "replica"
        primary_cluster_region: use1
        is_read_replica: true
        is_promoted_read_replica: false # False by default, added for visibility

Environment specific settings for dev as an example:

import:
  - catalog/aurora-mysql/replica/defaults

components:
  terraform:
    aurora-mysql/dev:
      metadata:
        component: aurora-mysql
        inherits:
          - aurora-mysql/defaults
          - aurora-mysql/replica/defaults
      vars:
        enabled: true
        primary_cluster_component: aurora-mysql/dev

Promoting the Read Replica

Promoting an existing RDS Replicate cluster to a fully standalone cluster is not currently supported by Terraform: https://github.com/hashicorp/terraform-provider-aws/issues/6749

Instead, promote the Replicate cluster with the AWS CLI command: aws rds promote-read-replica-db-cluster --db-cluster-identifier <identifier>

After promoting the replica, update the stack configuration to prevent future Terrafrom runs from re-enabling replication. In this example, modify stacks/catalog/aurora-mysql/replica/defaults.yaml

is_promoted_read_replica: true

Reploying the component should show no changes. For example, atmos terraform apply aurora-mysql/dev -s platform-use2-dev

Requirements

Name	Version
terraform	>= 1.0.0
aws	>= 4.0
random	>= 2.2

Providers

Name	Version
aws	>= 4.0
random	>= 2.2

Modules

Name	Source	Version
aurora_mysql	cloudposse/rds-cluster/aws	1.3.1
cluster	cloudposse/label/null	0.25.0
dns-delegated	cloudposse/stack-config/yaml//modules/remote-state	1.5.0
eks	cloudposse/stack-config/yaml//modules/remote-state	1.5.0
iam_roles	../account-map/modules/iam-roles	n/a
kms_key_rds	cloudposse/kms-key/aws	0.12.1
parameter_store_write	cloudposse/ssm-parameter-store/aws	0.11.0
primary_cluster	cloudposse/stack-config/yaml//modules/remote-state	1.5.0
this	cloudposse/label/null	0.25.0
vpc	cloudposse/stack-config/yaml//modules/remote-state	1.5.0
vpc_ingress	cloudposse/stack-config/yaml//modules/remote-state	1.5.0

Resources

Name	Type
random_password.mysql_admin_password	resource
random_pet.mysql_admin_user	resource
random_pet.mysql_db_name	resource
aws_caller_identity.current	data source
aws_iam_policy_document.kms_key_rds	data source
aws_partition.current	data source
aws_ssm_parameter.password	data source

Inputs

Name	Description	Type	Default	Required
additional_tag_map	Additional key-value pairs to add to each map in tags_as_list_of_maps. Not added to tags or id. This is for some rare cases where resources want additional configuration of tags and therefore take a list of maps with tag key, value, and additional configuration.	map(string)	{}	no
allow_ingress_from_vpc_accounts	List of account contexts to pull VPC ingress CIDR and add to cluster security group. e.g. { environment = "ue2", stage = "auto", tenant = "core" } Defaults to the "vpc" component in the given account	list(object({ vpc = optional(string, "vpc") environment = optional(string) stage = optional(string) tenant = optional(string) }))	[]	no
allowed_cidr_blocks	List of CIDR blocks to be allowed to connect to the RDS cluster	list(string)	[]	no
attributes	ID element. Additional attributes (e.g. workers or cluster) to add to id, in the order they appear in the list. New attributes are appended to the end of the list. The elements of the list are joined by the delimiter and treated as a single ID element.	list(string)	[]	no
aurora_mysql_cluster_family	DBParameterGroupFamily (e.g. aurora5.6, aurora-mysql5.7 for Aurora MySQL databases). See https://stackoverflow.com/a/55819394 for help finding the right one to use.	string	n/a	yes
aurora_mysql_cluster_parameters	List of DB cluster parameters to apply	list(object({ apply_method = string name = string value = string }))	[]	no
aurora_mysql_engine	Engine for Aurora database: aurora for MySQL 5.6, aurora-mysql for MySQL 5.7	string	n/a	yes
aurora_mysql_engine_version	Engine Version for Aurora database.	string	""	no
aurora_mysql_instance_parameters	List of DB instance parameters to apply	list(object({ apply_method = string name = string value = string }))	[]	no
auto_minor_version_upgrade	Automatically update the cluster when a new minor version is released	bool	false	no
context	Single object for setting entire context at once. See description of individual variables for details. Leave string and numeric variables as null to use default value. Individual variable settings (non-null) override settings in context object, except for attributes, tags, and additional_tag_map, which are merged.	any	{ "additional_tag_map": {}, "attributes": [], "delimiter": null, "descriptor_formats": {}, "enabled": true, "environment": null, "id_length_limit": null, "label_key_case": null, "label_order": [], "label_value_case": null, "labels_as_tags": [ "unset" ], "name": null, "namespace": null, "regex_replace_chars": null, "stage": null, "tags": {}, "tenant": null }	no
delimiter	Delimiter to be used between ID elements. Defaults to - (hyphen). Set to "" to use no delimiter at all.	string	null	no
descriptor_formats	Describe additional descriptors to be output in the descriptors output map. Map of maps. Keys are names of descriptors. Values are maps of the form {<br/> format = string<br/> labels = list(string)<br/>} (Type is any so the map values can later be enhanced to provide additional options.) format is a Terraform format string to be passed to the format() function. labels is a list of labels, in order, to pass to format() function. Label values will be normalized before being passed to format() so they will be identical to how they appear in id. Default is {} (descriptors output will be empty).	any	{}	no
eks_component_names	The names of the eks components	set(string)	[ "eks/cluster" ]	no
enabled	Set to false to prevent the module from creating any resources	bool	null	no
environment	ID element. Usually used for region e.g. 'uw2', 'us-west-2', OR role 'prod', 'staging', 'dev', 'UAT'	string	null	no
id_length_limit	Limit id to this many characters (minimum 6). Set to 0 for unlimited length. Set to null for keep the existing setting, which defaults to 0. Does not affect id_full.	number	null	no
is_promoted_read_replica	If true, do not assign a Replication Source to the Cluster. Set to true after manually promoting the cluster from a replica to a standalone cluster.	bool	false	no
is_read_replica	If true, create this DB cluster as a Read Replica.	bool	false	no
label_key_case	Controls the letter case of the tags keys (label names) for tags generated by this module. Does not affect keys of tags passed in via the tags input. Possible values: lower, title, upper. Default value: title.	string	null	no
label_order	The order in which the labels (ID elements) appear in the id. Defaults to ["namespace", "environment", "stage", "name", "attributes"]. You can omit any of the 6 labels ("tenant" is the 6th), but at least one must be present.	list(string)	null	no
label_value_case	Controls the letter case of ID elements (labels) as included in id, set as tag values, and output by this module individually. Does not affect values of tags passed in via the tags input. Possible values: lower, title, upper and none (no transformation). Set this to title and set delimiter to "" to yield Pascal Case IDs. Default value: lower.	string	null	no
labels_as_tags	Set of labels (ID elements) to include as tags in the tags output. Default is to include all labels. Tags with empty values will not be included in the tags output. Set to [] to suppress all generated tags. Notes: The value of the name tag, if included, will be the id, not the name. Unlike other null-label inputs, the initial setting of labels_as_tags cannot be changed in later chained modules. Attempts to change it will be silently ignored.	set(string)	[ "default" ]	no
mysql_admin_password	MySQL password for the admin user	string	""	no
mysql_admin_user	MySQL admin user name	string	""	no
mysql_backup_retention_period	Number of days for which to retain backups	number	3	no
mysql_backup_window	Daily time range during which the backups happen	string	"07:00-09:00"	no
mysql_cluster_size	MySQL cluster size	string	2	no
mysql_db_name	Database name (default is not to create a database	string	""	no
mysql_deletion_protection	Set to true to protect the database from deletion	string	true	no
mysql_enabled_cloudwatch_logs_exports	List of log types to export to cloudwatch. The following log types are supported: audit, error, general, slowquery	list(string)	[ "audit", "error", "general", "slowquery" ]	no
mysql_instance_type	EC2 instance type for RDS MySQL cluster	string	"db.t3.medium"	no
mysql_maintenance_window	Weekly time range during which system maintenance can occur, in UTC	string	"sat:10:00-sat:10:30"	no
mysql_name	MySQL solution name (part of cluster identifier)	string	""	no
mysql_skip_final_snapshot	Determines whether a final DB snapshot is created before the DB cluster is deleted	string	false	no
mysql_storage_encrypted	Set to true to keep the database contents encrypted	string	true	no
name	ID element. Usually the component or solution name, e.g. 'app' or 'jenkins'. This is the only ID element not also included as a tag. The "name" tag is set to the full id string. There is no tag with the value of the name input.	string	null	no
namespace	ID element. Usually an abbreviation of your organization name, e.g. 'eg' or 'cp', to help ensure generated IDs are globally unique	string	null	no
performance_insights_enabled	Set true to enable Performance Insights	bool	false	no
primary_cluster_component	If this cluster is a read replica and no replication source is explicitly given, the component name for the primary cluster	string	"aurora-mysql"	no
primary_cluster_region	If this cluster is a read replica and no replication source is explicitly given, the region to look for a matching cluster	string	""	no
publicly_accessible	Set to true to create the cluster in a public subnet	bool	false	no
regex_replace_chars	Terraform regular expression (regex) string. Characters matching the regex will be removed from the ID elements. If not set, "/[^a-zA-Z0-9-]/" is used to remove all characters other than hyphens, letters and digits.	string	null	no
region	AWS Region	string	n/a	yes
replication_source_identifier	ARN of a source DB cluster or DB instance if this DB cluster is to be created as a Read Replica. If this value is empty and replication is enabled, remote state will attempt to find a matching cluster in the Primary DB Cluster's region	string	""	no
ssm_password_source	If var.ssm_passwords_enabled is true, DB user passwords will be retrieved from SSM using var.ssm_password_source and the database username. If this value is not set, a default path will be created using the SSM path prefix and ID of the associated Aurora Cluster.	string	""	no
ssm_path_prefix	SSM path prefix	string	"rds"	no
stage	ID element. Usually used to indicate role, e.g. 'prod', 'staging', 'source', 'build', 'test', 'deploy', 'release'	string	null	no
tags	Additional tags (e.g. {'BusinessUnit': 'XYZ'}). Neither the tag keys nor the tag values will be modified by this module.	map(string)	{}	no
tenant	ID element _(Rarely used, not included by default)_. A customer identifier, indicating who this instance of a resource is for	string	null	no
vpc_component_name	The name of the VPC component	string	"vpc"	no

Outputs

Name	Description
aurora_mysql_cluster_arn	The ARN of Aurora cluster
aurora_mysql_cluster_id	The ID of Aurora cluster
aurora_mysql_cluster_name	Aurora MySQL cluster identifier
aurora_mysql_endpoint	Aurora MySQL endpoint
aurora_mysql_master_hostname	Aurora MySQL DB master hostname
aurora_mysql_master_password	Location of admin password in SSM
aurora_mysql_master_password_ssm_key	SSM key for admin password
aurora_mysql_master_username	Aurora MySQL username for the master DB user
aurora_mysql_reader_endpoint	Aurora MySQL reader endpoint
aurora_mysql_replicas_hostname	Aurora MySQL replicas hostname
cluster_domain	Cluster DNS name
kms_key_arn	KMS key ARN for Aurora MySQL

References

• cloudposse/terraform-aws-components - Cloud Posse's upstream component